NVIDIA GeForce GTX 260M SLI vs NVIDIA GeForce GTX 285M
NVIDIA GeForce GTX 260M SLI► remove
The Nvidia GeForce GTX 260M SLI is a combination of two Nvidia GeForce GTX 260M graphics cards for laptops linked together in SLI mode. The combination can be up to 40% faster than a single GTX 260M if given the proper game or driver support. In fact,some games may even run slower under SLI than with a single 260M if driver support is poor. Regardless, current consumption is twice as high as a single 260M. Notably, Nvidia drivers support the deactivation of SLI to save power. This is in contrast to the Catalyst drivers of the 4870 X2 at the time of our review.
The graphics memory of both cards can't be added and compared to single cards, as each card stores the same information. Therefore, a GTX 260M SLI with 2x512 graphics memory only counts as 512 MB for games.
As all SLI combinations, the GeForce 260M SLI may suffer from noticeable micro stuttering at frame rates between 20 to 30 fps. This is due to the inconsistent delays between subsequent frames being rendered and shown onscreen. As a result, an SLI combination may need higher frame rates for fluent gameplay.
Similar to other cards with DirectX 10 capabilities, the GeForce GTX 260M SLI combination renders 3D images using "Unified Shaders". Dedicated pixel shaders and vertex shaders have been dropped in favor of 2x112 stream processors for rendering graphic work that would have normally been done by specialized pixel and vertex shaders. Furthermore, the shader units are higher clocked than the chip at 1375 MHz.
The performance of the GTX 260M SLI is in the region of a single GTX 260M, but can be about 40 percent higher depending on application and driver support. A single GTX 260M is only a bit faster than a 9800M GTX due to the higher clock speed. For current DirectX 10 games like Crysis, World in Conflict, Bioshock or Age of Conan, the performance of this graphics card is sufficient with medium and high details. Older games and less demanding ones run fluently with high resolutions and full details. The memory component is up to 2x1024 MB GDDR3 with speeds up to 950MHz in MXM 3.0 boards or up to 800 MHz in MXM 2.0 boards.
An advantage of the GeForce GTX 260M SLI is the integrated PureVideo HD video processor. As a result, it is able to decode/encode H.264-, VC-1-, MPEG2- and WMV9 video material that would have otherwise been processed by the CPU. This ultimately allows the CPU to concentrate more on other tasks and programs simultaneously.
Both chips also support PhysX and CUDA applications. A single GTX 260M can also be used to calculate PhysX effects if supported by the game or application.
HybridPower is a technique to choose between the integrated (if available) and dedicated graphics core for power-saving purposes. So far, this works only in Windows Vista. Up to now, the user had to use a tool to switch between the GPUs. In the near future, Nvidia intends to be able to switch GPUs automatically in the drivers (now known as Optimus Technology, which is not supported by the GTX 260M SLI). GeForceBoost is not supported with this card as there would be no performance gain if one were to combine the integrated GPU with the dedicated 460M SLI.
The current consumption of up to 2x75 = 150 Watts (including the MXM board and VRAM) allows the use of the SLI cards only in laptops with a strong cooling system. Therefore, the GTX 260M SLI can be found only in heavier and larger desktop replacement (DTR) notebooks.
Compared with desktop graphics cards, the performance of the GTX 260M SLI is about on par with the GeForce 9800 GT SLI (600/1500/900).
NVIDIA GeForce GTX 285M► remove
The NVIDIA GeForce GTX 285M is a high-end graphic card of the 200M series based on the G92b core and most similar to the Desktop GeForce 9800 GTX+. Therefore the 285M cannot be directly compared to the Desktop GTX 285. The chip is produced in a 55nm fabrication process, which is a step up from the 65nm process of the GTX 9800M. Its 128 pipelines are all enabled as well, as opposed to only 112 pipelines of the GTX 9800M. Compared to the GTX 280M, the GTX 285M features a slightly higher clock speed and is therefore only marginally faster (3-6% on average).
An innovation in the 200M series is the much accelerated switch times if using Hybrid Power (lower than 1 second compared to 7 seconds at the 9800M GTX).
Similar to all other cards with native DirectX 10 capabilities, the GeForce GTX 285M renders 3D images using "Unified Shaders". In other words, there are no longer any more dedicated pixel shaders or vertex shaders. Instead, new stream processors (128 of them in the 285M) now process most of the heavy graphics loading that would have otherwise been done by dedicated pixel and vertex shaders. In fact, the shader units are clocked higher than the core chip itself.
As previously mentioned, the GTX 285M is about 3-6% faster than the GTX280M due to slightly higher clock speeds. This means that notebooks equipped with the GTX 285M should run all modern and demanding games (as of 2009) in high details and resolutions. Only very demanding games, like Crysis Warhead or Metro 2033, may become unplayable if at maximum graphical settings.
Games with PhysX support (e.g., Mirror's Edge) may benefit from improved performance out of the 285M. Still, the Mobility Radeon HD 5870 is arguably a faster and better value single core GPU for laptops.
An advantage of the GeForce GTX 285M is the integrated PureVideo HD video processor (VP2). With this software feature, the 285M can assist the CPU in the decoding of H.264-, VC-1-, MPEG2- or WMV9 videos.
HybridPower is an Nvidia power-saving technology for Windows Vista used for switching between integrated and dedicated graphics cards. In the future, Nvidia wants this switch to occur automatically with drivers (now known as Optimus). GeForceBoost is not supported with the 285M, as there would be no performance gain in combining the integrated GPU with the dedicated video card.
The power consumption can be up to 75 Watts (if including the MXM board and VRAM). As a result, the 285M is usually reserved for larger desktop replacement (DTR) laptops with powerful cooling solutions.
In June 2010, the GeForce GTX 480M (mobile Fermi) was announced with a revamped architecture compared to the GTX 285M. Compared to the 285M, the Fermi core will support DirectX 11 and offer better performance at the cost of higher power consumption levels and possibly higher heat output.
If compared to desktop graphics cards, the performance of the 285M can be considered somewhere in between the 9800 GT and the 9800 GTX, the latter of which is clocked considerably higher (675/1675/1100 MHz) in comparison.
|NVIDIA GeForce GTX 260M SLI||NVIDIA GeForce GTX 285M|
|GeForce GTX 200M Series|
|Cores||224 - unified||128 - unified|
|Core||550 MHz||576 MHz|
|Shader||1375 MHz||1500 MHz|
|Memory||950 MHz||1020 MHz|
|Bus||256 Bit||256 Bit|
|Max. Memory||2048 MB||1024 MB|
|DirectX||DirectX 10, 4.0||DirectX 10, 4.0|
|Transistors||1508 Million||754 Million|
|Technology||55 nm||55 nm|
|Features||HybridPower, PureVideo HD, CUDA, PhysX ready||HybridPower, PureVideo HD (VP2), CUDA, PhysX ready|
|MXM 3||MXM 3|